Electrical terminal



July 19, 1960 A. A. GRUNWALD ETAL 2,946,039

ELECTRICAL TERMINAL Filed Nov. 6, 1957 EVENTORS QrZT/zarQz TZZ 2,946,039 ELECTRICAL TERMINAL Arthur A. Grunwald, Edwards burg, Mich, and Raymond Ostrom, Mishawaka, Ind., assignors to Durakool, Incorporated, Elkhart, Ind., a corporation of Indiana Filed Nov. 6, 1957, Ser. No. 694,796

, 1 Claim. (Cl. 339-469) This invention relates, in general, to electrical terminals and in particular to a new and improved pressure type termination for electrical devices, for example, of a coil, relay, or a switch. A general object of this invention is an improvement over prior type electrical terminals of the pressure or clamp type which will allow the use of variable size wires, yet insure proper binding and holding of the wire as well as correct electrical carrying qualities.

Briefly, our invention contemplates structurally, two washers with radially extending points or teeth forming a star-shaped design and cooperating with a threaded fastener; one washer on or forming part of the threaded portion of a terminal permanently fixed to a base by any suitable means and the other washer on the shank portion of a screw, free to turn with respect to the shank yet, preferably captive thereon. A wire or conductor is placed between the two washers and, as the screw is turned in the threaded portion of the terminal, the teeth of the two washers interlock as in a set of gears binding the wire and producing a double result-keeping the wire from spreading out between the washers and holding the wire so that it cannot be pulled out even though the wire is not bent around the shank of the screw and regard less of the direction from which the wire was inserted between the washers normal to the shank of the screw. The free rotatability of the one washer with respect to the screw, contributes to this self-aligning interlocking characteristic of our terminal and in one embodiment, the freely rotatable washer is received about a reduced portion of the shank immediately below the screw head, while in another embodiment, the freely rotatable washer is received about an enlarged portion of the shank immediately below the screw head.

Accordingly, still another object of our invention is the provision of a screw type terminal with star-shaped washers, one of which is fixed to a base and the other of which is captive but free to rotate about the shank of the screw portion of the terminal, whereby a wire, inserted from any direction normal to the axis of the shank, will be held against spreading or movement when the screw is tightened so that the points of the stars of the washers interlocks Still another object of our invention is a new and improved pressure type terminal utilizing washers having radially extending points or teeth, one of which is free to move relative to the other whereby when a Wire is inserted therebetween, the teeth interlock to hold the wire permanently and insure correct electrical carrying qualities.

Other and more particular objects of my invention will be apparent to those skilled in the art from the following description and drawings forming a part hereof and wherein:

Fig. 1 is a top plan View illustrating to advantage the interlocking relationship of the teeth of an electrical terminal constructed in accordance with the teachings of our invention;

, 2 i Fig. 2 is a side elevational view illustrating to our invention in assembled relationship;

Fig. 3 is a side elevational view exploded to show the;

unassembled relationship of our electrical terminal;

Fig. 4 is a side elevational view partly in section partly broken away illustrating to advantage thecomponents of our electrical terminal; and

Fig. 5 is a side elevational view, partially section and partly broken away illustrating to advantage another embodiment of our invention. V 7

Turning now to the drawings, there is shown the e lec- I trical terminal, indicated in its entirety as 10, mounted on a bracket 11 (partially shown) which forms'a base.

The terminal 10 comprises aninternally threaded portion '12 (Figs. 4 and 5) into which is received in threadable relationship a screw 13 having external threads '14 and an enlarged head 15 of conventional shape was to be actuated by a screw driver or the like-into the threaded portion in the conventional manner. In this disclosure, the threaded portion comprises a rivet-type grommet 16 inserted in an aperture 17 in the base 11 and crimped and flanged as at 18 suitably afiixing the grommet 16 and one star-shaped washer 19 to the base 11.

The star-shaped washer 19, in this embodiment, is apertured, as at 20, to be inserted prior to assembly on the base over the grommet :16 inserted through aperture 17 from beneath base 11 and when the grommet 16 is crimped, the washer is held permanently and non-rotatably on the base 11. Obviously, the grommet 16 could be aifixed to the base 11 by any other suitable means, such as welding, brazing and the like, or the gronmiet 16 and the washer 19 could be made of one piece, if desired. Too, the grommet 16 could be inserted through the aperture in the washer '19 and through the aperture 17 from. the top of base 11, if desired.

A second star-shaped washer 21, centrally apertured as at 22, is received in one embodiment of our invention, in a slightly narrow neck portion 23 of the shank of the screw immediately adjacent the head 15 and so constructed and arranged to be free to rotate, yet preferably capthe wire from spreading out or from pulling from between the washers. The wire 24, as shown in the drawings-is secured or clamped between the aforementioned opposed inner annular portions 30 and 31 of washers 19 and 21, respectively. This important function of the interlocking of the teeth of our electrical terminal is largely accomplished by reason of the free rotatability of the washer 21 with'respect to the screw 13 which permit the washers to be self-aligning with respect to each other.

In another embodiment of our invention, as shown in Figure 5, washer 21 may be inserted about an enlarged portion 28 on the shank of the screw which is crirnped or otherwise formed after the washer is inserted thereon, as indicated at 29, to hold the washer 21 captive, yet permit its free rotation. V a r While we have shown our invention in connection with a solid type electrical wire or conductor, it is obvious that our terminal will accommodate stranded wire equally as well. Also, the size of the wire will dictate the size and Patented July19,--1.960"

advantage obliquely to hold a thicker wire therebetween than that shown herein.

While we have illustrated a grommet 16 for the purposes of this disclosure, a flanged and tapped bushing suitable for crimping or the like will 'sufiice equally as ,well and while we have described our invention with reference to a particular direction, it will be understood that this was done solely to facilitate description and such references relate only to the relative positions of the parts as shown in the accompanying drawing.

It is also understood that many changes and modifications may be made without departing from the spirit and scope of our invention; our invention being designed and comprehended within the appended claims which should be given a scope consistent with the prior art.

We claim:

An electrical terminal comprising, a base member, means affording a threaded opening extending through said base member, a first rwasher fixed against rotation relative to said base member and encircling said threaded opening, a screw having threaded engagement in said threaded opening, a second washer rotatably mounted about said screw and movable toward and away from said first washer upon inward and outward movement, respectively, of said screw in said threaded opening, said first and second washers having opposed inner annular portions for securing a conductor therebetween and radially outwardly extending teeth disposed in oblique relation relative to said inner annular portions, and opposed faces of said teeth of said first and second Washers lockingly interengaging with each other when the conductor is secured between said annular portions to limit relative rotation between said first and second washer.

References Cited in the file of this patent UNITED STATES PATENTS 1,427,807 Halblieb Sept. 5, 1922 2,044,679 Frese June 16, 1936 2,192,322 Mitchell Mar. 5, 1940 2,372,653 Becket Apr. 3, 1945 2,687,517 Despard Aug. 24, 1954 2,715,929 ,Knohl Aug. 23, 1955 

